Online research in philosophy

The philosophical account of vagueness I call "transvaluationism" makes three fundamental claims. First, vagueness is logically incoherent in a certain way: it essentially involves mutually unsatisfiable requirements that govern vague language, vague thought-content, and putative vague objects and properties. Second, vagueness in language and thought (i.e., semantic vagueness) is a genuine phenomenon despite possessing this form of incoherence—and is viable, legitimate, and indeed indispensable. Third, vagueness as a feature of objects, properties, or relations (i.e., ontological vagueness) is impossible, because of the mutually unsatisfiable conditions that such putative items would have to meet. In this paper I set forth the core claims of transvaluationism in a way that acknowledges and explicitly addresses a challenging critique by Timothy Williamson of my prior attempts to articulate and defend this approach to vagueness. I sketch my favored approach to truth and ontological commitment, and I explain how it accommodates the impossibility of ontological vagueness. I argue that any approach to the logic and semantics of vagueness that both (i) eschews epistemicism and (ii) thoroughly avoids positing any arbitrary sharp boundaries (either first-order or higher-order) will have to be not an alternative to transvaluationism but an implementation of it. I sketch my reasons for repudiating epistemicism. I briefly describe my current thinking about how to accommodate intentional mental properties with vague content within an ontology that eschews ontological vagueness. And I revisit the idea, which played a key role in my earlier articulations of transvaluationism, that moral conflicts provide an illuminating model for understanding vagueness.

A critical survey of the main theories about vagueness, organized in four main sections: (i) What is vagueness? (ii) Problems and paradoxes; (iii) Theories of vagueness; (iv) Vagueness and cognitive science.

Vagueness is an extremely widespread feature of language, famously associated with the sorites paradox. One instance of this paradox concludes that a single grain of sand is a heap of sand, by starting with a large heap of sand and invoking the plausible premise that if you take one grain of sand away from a heap of sand, then you still have a heap. The supervaluationist theory of vagueness states that a sentence is true if and only if it is true on all ways of making it precise. This yields borderline case predications that are neither true nor false, but yet classical logic is preserved almost entirely. The sorites paradox is solved because the main premise comes out false – on each way of making 'heap' precise, there is some first grain that turns a heap into a non-heap – but there is no sharp boundary to 'heap' because it is a different grain on different ways of making 'heap' precise; so, there is no grain of which it is true to say it is that first grain. The theory has a range of merits in comparison with rival theories, such as the epistemic view or degree theories of vagueness. Objections have been made (and answers offered) in relation to its treatment of higher-order vagueness and what it says about truth and validity. Author Recommends Fine, Kit. 'Vagueness, Truth and Logic.' Synthese 30 (1975). 265–300. Reprinted in Keefe and Smith 1997. This is the classic text introducing supervaluationism as a treatment of vagueness. It provides both philosophical discussion and formal modelling, demonstrating the adherence to classical logic that the theory yields. Keefe, Rosanna and Peter Smith, eds. Vagueness: A Reader . Cambridge, MA: MIT Press. This collection includes many classic papers on vagueness, including Fine's paper, cited above, a paper by Dummett that offers (but rejects) a precursor of the supervaluationist view, another less well-known early presentation of the view by Henyrk Mehlberg and discussion and defences of the main rival theories of vagueness. Keefe, Rosanna. Theories of Vagueness . Cambridge: Cambridge University Press, 2000. This book defends a supervaluationist theory of vagueness. It discusses the phenomena of vagueness and what is required of a theory of vagueness, before considering and rejecting the major alternatives in turn. Williamson, Timothy. Vagueness . London: Routledge, 1994. This book defends the epistemic theory of vagueness, which maintains that vague predicates do have sharp boundaries, we just do not know where those boundaries lie. It also contains detailed discussions of opposing theories, including supervaluationism. Unger, Peter. 'The Problem of the Many.' Midwest Studies in Philosophy 5 (1980). Eds. P.A. French, T.E. Uehling Jr and H.K. Wettstein. Minneapolis, MN: University of Minnesota Press. This is the classic presentation of the Problem of the Many, to which a supervaluationist solution is relatively popular. This problem arises because frequen

We all know that much in our thought and language, as well as much in the law, is vague. We are also reasonably good at recognizing cases of vagueness, even though most of us would be hard pressed to say exactly what vagueness is. In recent decades, there has been a flowering of work in the philosophy of logic and language attempting to do just that. Much of this work focuses on what it is for a word or phrase to be vague. The aim of this effort is to clarify what it is for a claim, question, command, or promise expressed using such a term to be vague, as well as what it is to reason with such terms. Different logico-linguistic theories have different conceptions of the scope of putative laws of classical logic, including bivalence (which states that every declarative sentence or proposition is either true or false) and excluded middle (which asserts all instances of A or ~A). In addition to this work in philosophical logic, recent decades have seen a growing interest in vagueness among legal scholars and philosophers of law. Here the focus is not so much on what legal vagueness is, which is generally assumed to be readily recognizable. Rather, it is on the extent and sources of vagueness in the law, the implications of vagueness for interpretation and adjudication, the systemic effects of vagueness, and the function – i.e. important positive value – of vagueness in certain areas of the law, as opposed to its disutility in others.1 To date, these two investigations of vagueness – in philosophical logic and the philosophy of law – have been largely independent of one another. This independence gives rise to a natural line of questioning. Can work in one domain contribute to work in..

Touching your mother's foot is incest because all the rest is a matter of degree (or so said Diogenes). That's just one expression of the puzzle of vagueness. Here's another: the passage of one second cannot mark the transition from being a pupa to being a butterfly--if something is a pupa at one time then in all close instants it remains a pupa; alas, it follows from this, via trivial logic, that there are no butterflies. Or again: it's vague where the Highlands of Scotland begin and end, so, a small step in the direction of London cannot mark the boundary between the Lowlands and the Highlands. But then it follows, via trivial logic, that one is unable to leave the Highlands (even when in London). What's driving these paradoxical arguments seems to be the very vagueness of the terms involved: such terms as 'incest', 'butterfly', 'pupa', 'The Highlands' are all vague and such vagueness seems to make them tolerant to marginal change. The puzzles of vagueness are not only deep (in that they admit of no uncontroversial and entirely satisfactory solution), they are also broad, for vague language is everywhere. In this course, you will be introduced to the various puzzles of vagueness and whether and how we might best address them. We will tackle such as questions as: Does the possibility of vagueness entail that there simply cannot be a logic of natural language? Does it entail that language is governed by inconsistent rules? Or does vagueness require some special or deviant logic? Is vagueness a special species of ignorance? Is the world, in some sense, vague? Is there an uncontroversial definition of vagueness or can we only isolate the phenomenon from within some substantive and controversial conception? What is higher-order vagueness and why is it considered to be such a puzzling phenomenon? Must the truth about vagueness be so strange? In what exact way are vague expressions tolerant?

Several philosophers offer explanations of linguistic vagueness by appealing to the referential context-dependence of vague terms. Timothy Williamson argues pre-emptively that any such approach must fail, on the grounds that context-dependence is neither necessary nor sufficient for vagueness. He supports this claim, in turn, by example. This paper argues that his examples fail to show that context-dependence is either unnecessary or insufficient for vagueness, and hence that he has failed by his own lights to show that it cannot explain vagueness.

Discussions of higher-order vagueness rarely define what it is for a term to have nth-order vagueness for n>2. This paper provides a rigorous definition in a framework analogous to possible worlds semantics; it is neutral between epistemic and supervaluationist accounts of vagueness. The definition is shown to have various desirable properties. But under natural assumptions it is also shown that 2nd-order vagueness implies vagueness of all orders, and that a conjunction can have 2nd-order vagueness even if its conjuncts do not. Relations between the definition and other proposals are explored; reasons are given for preferring the present proposal.

According to one account, vagueness is "metaphysical." The friend of metaphysical vagueness believes that, for some object and some property, there can be no determinate fact of the matter whether that object exemplifies that property. A second account maintains that vagueness is due only to ignorance. According to the epistemic account, vagueness is explained completely by and is nothing over and above our not knowing some relevant fact or facts. These are the minority views. The dominant position maintains that there is a third possible variety of vagueness, linguistic vagueness. And, it goes on to insist, all vagueness is of this third variety. I shall argue, however, that linguistic vagueness is not a third variety of vagueness. Either it is a species of metaphysical vagueness or a kind of ignorance. And this, I argue, makes trouble for the claim that all vagueness is linguistic.

In a seminal paper of 1923 on vagueness, Bertrand Russell discussed some of the most important problems concerning the nature of vagueness, its extension within the language, and its relation to truth and logic. The present paper inquires into Russell's theory. The following topics will be analysed and discussed in turn in sections 1?5: Russell's definition of vagueness; his claim that all phrases are vague; his theory of the source of the vagueness in our language; his principles for the transmission of vagueness; and his claim that logic is incompatible with vagueness. This paper is an attempt to give a rational reconstruction of Russell's position as expressed in his paper. Compatible passages in other of his works are also studied.

Most expressions in natural language are vague. But what is the best semantic treatment of terms like 'heap', 'red' and 'child'? And what is the logic of arguments involving this kind of vague expression? These questions are receiving increasing philosophical attention, and in this timely book Rosanna Keefe explores the questions of what we should want from an account of vagueness and how we should assess rival theories. Her discussion ranges widely and comprehensively over the main theories of vagueness and their supporting arguments, and she offers a powerful and original defence of a form of supervaluationism, a theory that requires almost no deviation from standard logic yet can accommodate the lack of sharp boundaries to vague predicates and deal with the paradoxes of vagueness in a methodologically satisfying way. Her study will be of particular interest to readers in philosophy of language and of mind, philosophical logic, epistemology and metaphysics.